Human tissue models, materials, and methods

ABSTRACT

Devices, systems, and methods appropriate for use in medical training that include materials that better mimic natural human tissue are disclosed. In one aspect, methods of forming multi-layer tissue simulations are provided. In another aspect, methods of forming a male genitalia model are provided. In another aspects, methods of forming an abdominal surgical wall insert are provided. Devices and systems associated with these methods are also provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to and the benefit of U.S.Provisional Patent Application No. 61/591,748, filed on Jan. 27, 2012,which is hereby incorporated by reference in its entirety.

BACKGROUND

As medical science has progressed, it has become increasingly importantto provide non-human interactive formats for teaching patient care.Non-human interactive devices and systems can be used to teach theskills needed to successfully identify and treat various patientconditions without putting actual patients at risk. Such trainingdevices and systems can be used by medical personnel and medicalstudents to learn the techniques required for proper patient care. Thetraining devices and systems can also be used by patients to learn theproper way to perform self-examinations.

As the use of non-human interactive training formats has increased, theneed for materials that simulate natural human tissue has alsoincreased. There have been earlier attempts to mimic characteristics ofnatural human tissues. For example, U.S. Patent Application PublicationNo. 2008/0076099 discloses human tissue phantoms and associated methodsof manufacturing that utilize two-component silicone gels covered by anylon fabric. Also, U.S. Pat. No. 5,805,665, U.S. Pat. No. 4,277,367,U.S. Pat. No. 5,902,748, and U.S. Pat. No. 6,675,035 each disclosevarious materials intended to simulate imaging properties of humantissue for various types of imaging techniques. Further, U.S. Pat. No.6,945,783 discloses a breast examination training system with inflatablenodules that simulate tumors within the breast tissue. While theseearlier attempts at mimicking aspects of natural human tissue have beenadequate in some respects, they have been inadequate in many respects.Accordingly, there remains a need for materials that better mimicnatural human tissue. In that regard, the training of medical personneland patients is greatly enhanced through the use of realistic hands-ontraining with devices and systems, such as those of the presentdisclosure, that better mimic characteristics of natural human tissuethan previous materials.

In view of the foregoing, there remains a need for devices, systems, andmethods appropriate for use in medical training that include materialsthat mimic natural human tissue.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure can be better understood from the followingdetailed description when read with the accompanying figures.

FIG. 1 is a perspective view of a patient simulator according to oneaspect of the present disclosure.

FIG. 2 is a perspective view of a plurality of tissue inserts for usewith the patient simulator of FIG. 1 according to various aspects of thepresent disclosure.

FIG. 3 is a perspective view of a portion of the patient simulator ofFIG. 1 illustrating a gluteus tissue insert according to one aspect ofthe present disclosure.

FIG. 4 a perspective view of a portion of the patient simulator of FIG.1 illustrating a deltoid tissue insert according to one aspect of thepresent disclosure.

FIG. 5 is a perspective view of a portion of the patient simulator ofFIG. 1 illustrating a thigh tissue insert according to one aspect of thepresent disclosure.

FIG. 6 is a perspective view of a portion of the patient simulator ofFIG. 1 illustrating a thigh tissue insert similar to that of FIG. 5, butaccording to another aspect of the present disclosure.

FIG. 7 is a perspective view of a portion of the patient simulator ofFIG. 1 illustrating a thigh tissue insert similar to that of FIGS. 5 and6, but according to yet another aspect of the present disclosure.

FIG. 8 is a top view of a pair of tissue inserts illustrating additionalaspects of the present disclosure.

FIG. 9 is a diagrammatic cross-sectional side view of a tissue insertaccording to an aspect of the present disclosure.

FIG. 10 is a perspective, exploded view of a molding system configuredto produce the tissue insert of FIG. 9 according to an embodiment of thepresent disclosure.

FIG. 11 is a perspective, assembled, partially translucent view of themolding system of FIG. 10.

FIG. 12 is a side, partially translucent view of the molding system ofFIGS. 10 and 11.

FIG. 13 is a perspective, exploded view of a molding system configuredto produce a thigh tissue insert according to an embodiment of thepresent disclosure.

FIG. 14 is a perspective, assembled, partially translucent view of themolding system of FIG. 13.

FIG. 15 is a perspective view of a male genitalia model according to anembodiment of the present disclosure.

FIG. 16 is a back view of the male genitalia model of FIG. 15.

FIG. 17 is a perspective view of a molding system configured to producethe male genitalia model of FIGS. 15 and 16 according to an embodimentof the present disclosure.

FIG. 18 is a top view of the molding system of FIG. 17.

FIG. 19 is an exploded top view of a patient simulator having a surgicaltummy cover according to another embodiment of the present disclosure.

FIG. 20 is a perspective view of a surgical insert for the surgicaltummy cover of the patient simulator of FIG. 19 according to anembodiment of the present disclosure.

FIG. 21 is a side view of the surgical insert of FIG. 20.

FIG. 22 is a perspective, exploded view of a molding system configuredto produce at least a portion of the surgical insert of FIGS. 20 and 21according to an embodiment of the present disclosure.

FIG. 23 is a side view of an intermediate stage of manufacture of thesurgical insert of FIGS. 20 and 21 according to an embodiment of thepresent disclosure.

FIG. 24 is a perspective, exploded view of a molding system configuredto produce at least a portion of the surgical insert of FIGS. 20 and 21according to an embodiment of the present disclosure.

FIGS. 25-30 illustrate a series of manufacturing steps using the moldingsystem of FIG. 24 according to an embodiment of the present disclosure.

FIG. 31 is a perspective view of a support structure configured for usewith a surgical insert according to an embodiment of the presentdisclosure.

FIG. 32 is a bottom view of the support structure similar to that ofFIG. 31 assembled with a surgical insert according to an embodiment ofthe present disclosure.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

For the purposes of promoting an understanding of the principles of thepresent disclosure, reference will now be made to the embodimentsillustrated in the drawings, and specific language will be used todescribe the same. It is nevertheless understood that no limitation tothe scope of the disclosure is intended. Any alterations and furthermodifications to the described devices, systems, and methods, and anyfurther application of the principles of the present disclosure arefully contemplated and included within the present disclosure as wouldnormally occur to one skilled in the art to which the disclosurerelates. In particular, it is fully contemplated that the features,components, and/or steps described with respect to one embodiment may becombined with the features, components, and/or steps described withrespect to other embodiments of the present disclosure. For the sake ofbrevity, however, the numerous iterations of these combinations will notbe described separately.

Referring initially to FIG. 1, shown therein is a patient simulator 100.In the illustrated embodiment, the patient simulator 100 is a full bodypatient simulator. To that end, the patient simulator 100 includes atorso 102, legs 104, arms 106, and a head 108. The various anatomicalportions of the patient simulator 100 are sized, shaped, and formed of asuitable material to mimic natural human anatomy. The patient simulator100 can be either a male simulator or a female simulator and willinclude appropriate anatomical features based on the simulated gender.Further, in some instances, the patient simulator 100 includes asimulated circulatory system, a simulated respiratory system, and/orother simulated aspects. In that regard, the patient simulator 100 is incommunication with a control system configured to control thecirculatory system, respiratory system, and/or other aspects of thepatient simulator. For example, in some instances, the control system isconfigured to adjust parameters associated with the circulatory system,respiratory system, and/or other aspects of the patient simulator 100 inaccordance with a simulation scenario and/or a user's application oftreatment to the patient simulator 100 based on the simulation scenario.

Accordingly, in some instances, the patient simulator 100 includes oneor more features as described in U.S. patent application Ser. No.13/223,020, filed Aug. 31, 2011, now U.S. Pat. No. 8,419,438, U.S.patent application Ser. No. 13/031,116, filed Feb. 18, 2011, now U.S.Pat. No. 8,517,740, U.S. patent application Ser. No. 13/031,087, filedFeb. 18, 2011, now U.S. Pat. No. 8,678,831, U.S. patent application Ser.No. 13/031,102, filed Feb. 18, 2011, now U.S. Pat. No. 8,608,483, U.S.patent application Ser. No. 12/856,903, filed Aug. 16, 2010, now U.S.Pat. No. 8,152,532, U.S. patent application Ser. No. 12/708,682, filedFeb. 19, 2010, now U.S. Pat. No. 8,740,624, U.S. patent application Ser.No. 12/708,659, filed Feb. 19, 2010, now U.S. Pat. No. 8,500,452, U.S.patent application Ser. No. 11/952,606, filed Dec. 7, 2007, now U.S.Pat. No. 8,696,362, U.S. patent application Ser. No. 11/952,669, filedDec. 7, 2007, now U.S. Publication No. 2009-0148822, U.S. Pat. No.8,016,598, U.S. Pat. No. 7,976,313, U.S. Pat. No. 7,976,312, U.S. Pat.No. 7,866,983, U.S. Pat. No. 7,114,954, U.S. Pat. No. 7,192,284, U.S.Pat. No. 7,811,090, U.S. Pat. No. 6,758,676, U.S. Pat. No. 6,503,087,U.S. Pat. No. 6,527,558, U.S. Pat. No. 6,443,735, U.S. Pat. No.6,193,519, and U.S. Pat. No. 5,853,292, and U.S. Pat. No. 5,472,345,each of which is hereby incorporated by reference in its entirety.

Further, in some instances, the patient simulator 100 includes one ormore features as provided in medical simulators provided by GaumardScientific Company, Inc. based out of Miami, Fla., including but notlimited to the following models: S1000 Hal®, S1020 Hal®, S1030 Hal®,S3000 Hal®, S2000 Susie®, S221 Clinical Chloe, S222 Clinical Chloe,S222.100 Super Chloe, S303 Code Blue®, S304 Code Blue®, S100 Susie®,S100 Simon®, S200 Susie®, S200 Simon®, S201 Susie®, S201 Simon®, S203Susie®, S204 Simon®, S205 Simple Simon®, S206 Simple Susie®, S3004Pediatric Hal®, S3005 Pediatric Hal®, S3009 Premie Hal®, S3010 NewbornHal®, S110 Mike®, S110 Michelle®, S150 Mike®, S150 Michelle®, S107Multipurpose Patient Care and CPR Infant Simulator, S117 MultipurposePatient Care and CPR Pediatric Simulator, S157 Multipurpose Patient Careand CPR Pediatric Simulator, S575 Noelle®, S565 Noelle®, S560 Noelle®,S555 Noelle®, S550 Noelle®, S550.100 Noelle, and/or other patientsimulators.

Referring now to FIG. 2, shown therein is a set 110 of multi-layertissue constructs suitable for use with the patient simulator 100. Inparticular, a gluteus tissue insert 112, a deltoid tissue insert 114, athigh tissue insert 116, and a thigh tissue insert 118 are shown.However, it will be apparent from the following description that similartissue inserts can be created for virtually any portion of the humanbody that includes a skin layer. As will be discussed below, themulti-layer tissue constructs described herein provide injection andsurgical inserts that can be used with existing manikins and/orincorporated into new manikins. The inserts provide a closerapproximation to the human anatomy they represent by appropriatelyreplicating the various natural tissue layers associated with suchanatomy including, for example, skin, subcutaneous, fascia, and muscle,to provide a realistic model on which injection and surgical techniquescan be taught. In that regard, the multi-layer tissue models of thepresent disclosure aims to provide a more accurate representation of thetissue layers involved in subcutaneous injection, intramuscularinjection, surgical techniques, wound closure techniques, and dermalsuture removal. By providing anatomically relevant layers, familiaritywith needle, scalpel, and suture techniques can be achieved in a systemthat provides realistic tactile feedback. These skills can be obtainedin a stress-free environment so that a medical practitioner isadequately trained prior to work on a live patient.

As noted above, the inserts shown in FIG. 2 are configured for thethigh, deltoid, and gluteus regions, but the applicable tissue regioncan be expanded to include any region of the body where the skin,subcutaneous, fascia, and/or muscle layers need to be represented. Inthat regard, such tissue inserts are suitable for training a variety ofmedical procedures across the body, including, but not limited to,insertion of chest drains, tension pneumothorax cut-down sites, andspine injection simulators. Further, as will be discussed in greaterdetail below, the tissue inserts include various types of wounds,including open wounds for training of treatment of open wounds,partially healed suture lines that can be used for training of sutureremoval techniques, and/or other wound variations

Each of the multi-layer tissue inserts is manufactured to accuratelyconform to existing manikin geometry. In that regard, the insert istypically sized and shaped to be received within an opening of themanikin at an appropriate anatomical location. Further, when seatedwithin the opening and secured to the manikin, the outer surface of thetissue insert (e.g., the skin layer) is typically flush with thesurrounding outer layer of the manikin such that the insert provides anapproximate continuation of the natural outer surface of the manikin. Inthat regard, FIGS. 3-6 each illustrate the positioning of a tissueinsert within the manikin. In particular, FIG. 3 shows the gluteustissue insert 112 and the thigh insert 116 positioned withincorresponding portions of the patient simulator 100. FIG. 4 illustratesthe deltoid insert 114 positioned within the arm 106 of the patientsimulator 100. FIG. 5 illustrates the thigh insert 116 positioned withinthe leg 104 of the patient simulator 100. FIG. 6 illustrates the thighinsert 118 positioned within the leg 104 of the patient simulator 100.The thigh insert 118 includes a partially healed suture line 120. FIGS.7 and 8 illustrate alternative wounds that can be included on any of thetissue inserts of the present disclosure. In that regard, FIG. 7 shows athigh insert 122 having an open wound 124 formed thereon. FIG. 8 shows atissue insert 130 simulating an initial stage of ulceration for adecubitus ulcer and a tissue insert 132 simulating a deeply infectedstage of ulceration of a decubitus ulcer.

Note, generally, how the inserts fit into the recesses or openings inthe patient simulator 100, thereby allowing training procedures to becarried out in situ. In that regard, the insert pads can be used forvarious procedures including: subcutaneous injection, intramuscularinjection, surgical techniques, and/or wound closure techniques.Further, since the inserts are easily replaceable, multiple trainingprocedures can be performed using the same patient simulator 100 bysimply exchanging a used insert for a new insert. Further still, in manyinstances the inserts are suitable for use in multiple trainingprocedures, such that a single insert can be used to train many usersbefore needing replacement.

Generally, the tissue inserts 112, 114, 116, 118, and 122 have a similarlayered structure, but relative thicknesses of the layers and the sizeand shape of the insert are adjusted to properly simulate the desiredanatomical feature. Generally, the tissue inserts of the presentdisclosure consist of four to five layers, namely the skin,subcutaneous, fascia, muscle, and a backing. In some instances, themuscle layer and the backing are integrally formed of the same materialsuch that muscle and backing may be considered to be a single layer. Forsake of clarity, the layered structure of the tissue inserts 112, 114,116, 118, and 122 will be described in relation to the gluteus insert112 illustrated in FIG. 9. As shown, the gluteus insert 112 includes askin layer 134. In the illustrated embodiment, a cylindrical wall 136extends from the skin layer 134. In some instances, the wall 136 isintegrally formed with the skin layer 134 and defines a cavity forforming the remaining layers of the insert 112. In the illustratedembodiment, a subcutaneous layer 138 is formed adjacent the skin layer134 within the cavity defined by wall 136. A fascia layer 140 is formedadjacent the subcutaneous layer 138. A muscle layer 142 is formedadjacent to the fascia layer 140. In the illustrated embodiment, themuscle layer 142 also forms the backing of the insert 112. Accordingly,a separate backing layer is not illustrated. However, in otherembodiments, a backing layer separate from the muscle layer 142 isincluded.

Dependent on the particular location on the body that the insertrepresents, the respective thickness of the above-mentioned layers isadjusted to create a realistic model. Further, each layer is pigmentedaccording to the anatomical tissue layer it represents. The layers areformed from materials having appropriate mechanical properties such thatwhen injecting needle into the insert, there is a distinct differencewhen the needle has passed through the skin layer 134 into thesubcutaneous layer 138, and then again when it passes into the musclelayer 142. Generally, the resistance decreases when passing through theskin layer 134 to the subcutaneous and fascia layers 138, 140 and thenincreases when the needle reaches the muscle layer 142. In that regard,the resistance of the muscle layer 142 is greater than that of the skinlayer 134. Table 1 provides an exemplary range of skin and subcutaneouslayer thicknesses for the thigh, gluteus, and deltoid regions, and anexemplary specific thickness adopted for the inserts shown in FIG. 2above.

TABLE 1 Exemplary skin and subcutaneous layer thicknesses for gluteus,deltoid, and thigh tissue inserts. All measurements in millimeters.Gluteus Deltoid Thigh Sub- Sub- Sub- Skin cutaneous Skin cutaneous Skincutaneous Mean −3SD 0.97 N/A 0.91 N/A 0.7 N/A Mean 2.41 15.45 2.23 10.771.87 10.35 Mean +3SD 3.85 37.26 3.55 27.63 3.04 27.3 Model 3.5 16.0 3.010.0 3.0 11.0

In some instances, the tissue inserts of the present disclosure aremanufactured in a mold that includes a two-component cavity mold, acore, and a bridge. The shapes of the mold components have varyingdegrees of complexity based on the tissue model being manufactured. Insome instances, the mold components are formed of machined aluminum 6061that are designed in a 3D CAD system such as SolidWorks or Rapidform,and have a matte surface finish that is obtained by bead blasting. Mosttissue models include undercuts, so a split cavity mold is required toallow machining of the mold components and to improve de-molding.Aluminum 6061 was selected as a mold material due to the fact that it islight-weight and has superior heat transfer properties for those stepsthat require cure at elevated temperatures. However, any other suitablemold materials may be utilized as would be recognized by those skilledin the art. Further, the cores are typically designed to ensure aconstant thickness of the skin layer, which is continuous with the sidewalls. However, in some circumstances, the core may be shaped to providea varying thickness to the skin layer and/or the sidewalls of the tissueinsert.

Referring now to FIGS. 10-12, shown therein are aspects of a moldingsystem 150 suitable for manufacturing the gluteus insert 112 describedabove according to an embodiment of the present disclosure. In thatregard, the molding system 150 includes a lower component 152 having alower cavity 154 shaped to define the outer surface of the skin layer ofthe gluteus insert. An upper component 156 is configured to mate withthe lower component 152 and includes an opening extending therethroughfor receiving a core 160. In the illustrated embodiment, the opening 158has a circular cross-section and the core 160 has a generallycylindrical shape configured to be received within the circularcross-section of the opening. In that regard, the diameter of the core160 is smaller than the diameter of the opening 158 such that a space174 remains around the core. In that regard, the space 174 will befilled with material injected into the mold system 150. In someembodiments, the space around the core 160 is utilized to form the wall136 that defines the cavity that receives the remaining layers of thegluteus insert. Accordingly, in some instances it is desirable for thecore 160 to be coaxial with the opening 158 such that the wall 136 has asubstantially constant thickness. To that end, the core 160 is coupledto a bridge 162 that facilitates alignment and coupling of the moldsystem 150. In that regard, the lower component 152 includes openings164 for receiving fasteners 166 that engage upper component 156. In someinstances, the fasteners 166 are threaded and the upper component 156includes threaded openings configured to receive and mate with thethreaded fasteners. However, any suitable manner of releasably securingthe lower component 152 to the upper component 156 may be utilized.Similarly, the bridge 162 includes openings 168 for receiving fasteners170 that engage corresponding openings 172 in the upper component.Again, in some instances, the fasteners 170 are threaded and theopenings 172 are threaded to receive and mate with the threadedfasteners. However, any suitable manner of releasably securing thebridge 162 and core 160 to the upper component 156 may be utilized.

Referring now to FIGS. 13 and 14, shown therein are aspects of a moldingsystem 200 suitable for manufacturing the thigh insert 116 describedabove according to an embodiment of the present disclosure. In thatregard, the molding system 200 includes a lower component 202 having alower cavity 204 shaped to define the outer surface of the skin layer ofthe gluteus insert. An upper component 206 is configured to mate withthe lower component 202 and includes a contoured surface 208 and a lip210 for defining structural aspects of the resulting tissue insert.Further the upper component 206 includes an opening 212 extendingtherethrough. In the illustrated embodiment, the opening 212 has agenerally elliptical or oval shape. The molding system 200 also includesa core 214 configured to be placed, at least partially, through theopening 212 of the upper component 206. The core 214 also has agenerally elliptical or oval outer profile such that it can be receivedwithin the opening 212 of the upper component. In that regard, the core214 is sized and shaped such when the mold system 200 is assembled, asshown in FIG. 14, the bottom surface of the core is generally equallyspaced from the cavity 204 of the lower component 202 such that a skinlayer produced using the molding system will have a substantiallyconstant thickness. Accordingly, in some instances it is necessary toalign the core 214 with the lower and/or upper components 202, 206. Tothat end, the core 214 is coupled to a bridge 216 that facilitatesalignment and coupling of the mold system 200. The bridge 216 includes ahandle 218. In that regard, the lower component 202 includes openings220, 222, and 224, while the upper component 206 includes openings 226and 228 along with an alignment structure 230. Further, the bridge 216includes openings 232 that are configured to interface with thealignment structure(s) 230 of the upper component 206. Generally, theopenings 220, 222, 224, 226, and 228 of the lower and upper components202, 206 are configured to receiving fasteners that secure the lower andupper components 202, 206 together. In some instances, the fasteners 166are threaded and include a nut. In other instances, at least one of theopenings is threaded and configured to receive a threaded fastener.However, any suitable manner of releasably securing the lower component202 to the upper component 206 may be utilized. Similarly, any suitablemanner of releasably securing the bridge 216 and core 214 to the uppercomponent 206 may be utilized. The bridge 216 also includes a recess234.

When using the molding systems 150, 200 or other similar molding system,the first formed layer of the insert forms the skin. In some instances,it is manufactured from a platinum-cured silicone thermoset or aplatinum-cured silicone thermoset blend with a shore hardness as low as00-10 but no higher than 30 A. Silicone pigments are added to representlight, medium, or dark skin tones. In some embodiments, two or moredifferent platinum-cured silicones are blended to optimize hardness,needle puncture, tissue cutting, and suture retention. In someinstances, higher durometer materials provide optimized tear strengthfor suture retention, but they are too hard to replicate the feel ofskin. In order to achieve the best of both worlds, it becomes necessaryto blend materials with a higher shore hardness with materials with alower shore hardness, resulting in a product whose shore hardness fallsin between the two extremes, based on the ratio of the mixture. Asilicone blend featuring a platinum-cured silicone thermoset with ashore hardness of 00-45 (TC 5101, BJB Enterprises, Tustin, Calif.) and aplatinum-cured silicone thermoset with a shore hardness of 10 A (DragonSkin® 10 Medium, Smooth-On, Inc., Easton, Pa.) has been found by theinventors to be most successful for use as a skin material that has toendure needle puncture, cutting, and suture retention. The recommendedpercentage of 00-45 ranges from 0-100%, where the preferred blend setsthe ratio between the 00-45 and 10 A materials to 1:1.

The second formed layer of the insert forms the subcutaneous or fatlayer. In some instances, this layer is manufactured from a blend ofsilicone foam, silicone thermoset, and silicone oil with added pigmentsfor color matching. In some implementations, the silicone foam is asoft, two-component, platinum silicone castable foam; the siliconethermoset is a platinum-cured silicone thermoset with a shore hardnessas low as 00-10 but no higher than 00-30; and the silicone oil is apolydimethyl siloxane with a viscosity between 80-110 centipose. In oneembodiment, the silicone foam (Soma Foama, Smooth-On, Inc., Easton, Pa.)ranges from 10-35% of the total weight, the silicone thermoset has ashore hardness of 00-10 (Silicone 99-255, Smooth-On, Inc., Easton, Pa.)and ranges from 15-60% of the total weight, and the silicone oil(TC-5005 C, BJB Enterprises, Tustin, Calif. or F-100, SILPAK, Inc.,Pomona, Calif.) ranges from 10-60% of the total weight. The preferredblend to optimize the realism of the subcutaneous layer sets thepercentage of foam to 13%, the percentage of silicone thermoset to 25%,and the percentage of oil (TC-5005 C, BJB Enterprises, Tustin, Calif.)to 62%. This blend creates a layer that accurately represents thehardness and consistency of the subcutaneous layer while allowingrealistic blunt dissection.

The third formed layer of the insert forms the fascia. This is a denselayer of connective tissue that is resistant to unidirectional tensionforces and surrounds muscles, organs, and other soft structures. In someinstances, Tyvek is utilized to form the fascia as it responds in amanner similar to the fascia when punctured, cut, and/or sutured. Insome specific instances, the material used is Tyvek® Soft Structure Type14 (DuPont, Wilmington, Del.) as this is a flexible fabric-like softstructure with good tear resistance. Tyvek is a spunbonded olefinmaterial.

The fourth formed layer of the insert forms the muscle. As discussedabove, the muscle layer offers greater resistance to needle puncturewhen compared to the skin and subcutaneous layers. As a consequence, theshore hardness of this layer must be greater than that of the skin andsubcutaneous layers. Accordingly, in some instances the muscle layer ismanufactured from a platinum-cured silicone thermoset with a shorehardness from 10 A to 50 A, and silicone pigments are added to providerealistic coloring. In one specific embodiment, the muscle layer isformed of a silicone thermoset with a shore hardness of 10 A (DragonSkin® 10 Medium, Smooth-On, Inc., Easton, Pa.) as this most closelyapproximates the properties of the muscle layer.

The fifth formed layer forms the backing or back skin. Generally, thepurpose of this layer is to encapsulate the muscle, fascia, andsubcutaneous layers while providing a surface that sits within theinsert's recess in the manikin. Accordingly, in some instances thebacking is shaped to mate with corresponding structural features of thepatient simulator and, in particular, the opening or recess into whichthe insert is designed to be placed. In some instances, the backinglayer is manufactured from a platinum-cured silicone thermoset with ashore hardness ranging from 00-10 to 30 A. Generally, the backing layershould not be any harder than 30 A as this will present a distinctintersection between the skin layer and back layer. It is desirable insome instances to match the durometer of the back layer to that of theinsert skin itself. Silicone pigments are added to provide realisticcoloring and a color match to the skin layer. Accordingly, in someinstances, the material used as the backing is a platinum-cured siliconethermoset blend such as that used for the skin. A silicone blendfeaturing a silicone thermoset with a shore hardness of 00-45 (TC 5101,BJB Enterprises, Tustin, Calif.) and a platinum-cured silicone with ashore hardness of 10 A (Dragon Skin® 10 Medium, Smooth-On, Inc., Easton,Pa.) that is mixed in a ratio of 1:1 is utilized in some instances.

One suitable technique for manufacturing a tissue model insert accordingto the present disclosure will now be described. No limitation isintended hereby and those skilled in the art will recognize that manydifferent modifications and/or alternative manufacturing techniques maybe utilized, including the use of alternative materials. In oneparticular embodiment, a thigh insert is manufactured using thefollowing steps:

-   1) Manufacture of Skin Layer:    -   a) Clean the mold and liberally apply mold release.    -   b) Prepare the Skin Mixture (Materials: Dragon Skin 10 Medium &        TC 5101)        -   i) Measure 50 g Dragon Skin Part B, add 50 g TC 5101 Part B,            add 0.4 g Silc Pig Fleshtone, add 1 drop of FuseFX Rosy            Skin, add 2 Drops of FuseFX Light Skin, mix until a uniform            color        -   ii) Add 50 g Dragon Skin 10 Part A, add 50 g TC 5101 Part A    -   c) Mix and Vacuum until all bubbles are removed    -   d) Pour the Skin Mixture into the mold making sure to start        pouring at the lowest point. Pour entire contents into the mold.    -   e) Slowly place the mold core into position, making sure that        the material doesn't overflow onto the top of the mold core.    -   f) Allow to cure for 30 minutes at 100° C.    -   g) Remove insert (leaving the skin in place) and clean the inner        surface of the outer skin with isopropanol to remove any mold        release residue.-   2) Manufacture of Fat Layer    -   a) Prepare the Foam Mixture (Materials: Soma Foama, Silicone        99-255, & TC 5005C)        -   i) Measure 10.4 g Soma Foama Part A, add 16.2 g Silicone            99-255 Part A, add 72 g TC 5005C, add 3 drops of Silc Pig            Yellow, mix until uniformly distributed        -   ii) Add 5.2 g Soma Foama Part B, add 16.2 g Silicone 99-255            Part B        -   iii) Mix until bubble formation and reaction begins, and            mixture begins to thicken (approximately 8 minutes at 73°            F.).    -   b) Transfer the mixture to the mold, and continue to mix until        material starts to set    -   c) Allow it to cure for 2 hours at room temperature.    -   d) If the foam expands above the height of the Skin, trim it so        that it sits just below it.-   3) Secure the Fascia    -   a) Cut a piece of Tyvek Sheet (Tyvek® Type 14) to match the        shape of the cavity above the fat layer    -   b) Place a thin layer of silicone adhesive (Sil-Poxy©) over one        side of the Tyvek Sheet, and lay the sheet over the fat layer so        that the adhesive faces the fat layer. Smooth the Tyvek onto the        fat layer, making sure there is no entrapped air.    -   c) Allow to cure for 30 minutes at room temperature.-   4) Manufacture of Muscle Layer    -   a) Prepare the Muscle Layer Mixture (Material: Dragon Skin 10        Medium)        -   i) Measure 50 g Part B, add 10 drops of Silc Pig Blood, mix            until a uniform color        -   ii) Add 50 g Part A        -   iii) Mix and Vacuum until all bubbles are removed    -   b) Pour the mixture into the mold slowly, making sure not to        entrap air during the process. Allow to sit for 5 minutes, and        burst all air bubbles    -   c) Cure for 30 minutes at 100° C.-   5) Manufacture of Backing    -   a) Prepare the Backing Mixture (Material: Dragon Skin 10 Medium        & TC 5101):        -   i) Measure 25 g Dragon Skin Part B, add 25 g TC 5101 Part B,            add 0.2 g Silc Pig Fleshtone, add 1 drop of FuseFX Rosy            Skin, add 2 Drops of FuseFX Light Skin, mix until a uniform            color        -   ii) Add 25 g Dragon Skin 10 Part A, add 25 g TC 5101 Part A    -   b) Mix and Vacuum until all bubbles are removed    -   c) Pour the Backing Mixture over the muscle layer, making sure        not to entrap air during the process. Allow to sit for 5        minutes, and burst all air bubbles    -   d) Allow to cure for 30 minutes at 100° C.-   6) Gently remove from mold, clean all mold release of with a mild    soapy solution, dry and apply talc.-   7) Inspect.

As noted above, in some instances it is useful to expand the basicmulti-layer tissue inserts to include realistic products for training ofsuture removal, wound cleaning, packing, dressing, etc. This can beincorporated with the above materials through the use of sculpted modelsthat replicate the geometry of a variety of wounds, including, but notlimited to, decubitus ulcers, tropical ulcers, gunshot wounds, and cuts.These products can be manufactured from a multi-layer tissue constructas described above, but in some cases, it is beneficial to manufacturethe product from a homogeneous platinum-cured silicone thermoset such asthat used for the skin layer (with a shore hardness as low as 00-10 butno higher than 30 A). Wound detailing can be achieved through the use ofpigments and silicone compatible paints, such as the M, F, and LY seriespaints (FuseFX, Ottawa, ON, Canada) or the Psycho Paint® PlatinumSilicone Paint Base (Smooth-On, Inc., Easton, Pa.).

As with the standard model inserts, these models can be fit directlyinto recesses in the manikin. For example, a suture removal thigh model124 is illustrated in FIG. 6 received within the leg of a patientsimulator. This model 118 can replace a standard leg insert, and itincludes a raised, partially healed leg wound that can hold a standardsuture and can be used to train medical personnel on appropriate sutureremoval techniques. This model 118 is a multi-layer model that includesthe skin, subcutaneous, fascia, and muscle layers, and additionalpigmenting/painting is included on the scar line to improve realism.FIG. 7 shows a tropical ulcer wound overlay 124 for a thigh modelinsert. The wound overlay 124 and can be placed on any region of themanikin. In some instances, the wound overlay 124 is manufactured from a00-30 platinum-cured silicone thermoset (Ecoflex® 0030, Smooth-On, Inc.,Easton, Pa.) that is painted with a combination of silicone paints(M-Series and F-Series, FuseFX, Ottawa, ON, Canada) to enable woundrealism. The wound overlay 124 can be used to train wound cleaning,packing, and dressing. FIG. 8 shows two different decubitus ulcers atdifferent stages. Namely, ulcer 130 is in the early stages, whereasulcer 132 is advanced. Such ulcers can be used on any portion of thepatient simulator and used for training wound cleaning, packing, anddressing. The decubitus ulcers 130, 132 can be manufactured as either amulti-layer construct, such as that adopted for the tissue model insertsdiscussed above, or as a homogeneous silicone thermoset, such as thatused for the wound overlay. Again, the application of silicone paintsaid in wound realism.

The tissue model inserts of the present disclosure provide a betterrefined multi-layer tissue construct that accurately represents theskin, subcutaneous, fascia, and muscle layers. The improvements made tothe layers have increased the functionality and realism of the tissueinserts. These tissue model inserts provide a cost-effective platformfor the training of subcutaneous injection, intramuscular injection,surgical techniques, wound closure techniques, and dermal sutureremoval. In the case of injection, the skin layer reseals and can bere-used multiple times for the training of this procedure. The insertsprovide a close approximation to an actual patient, thereby creating amore realistic training model. The inserts are disposable inserts thatcan be incorporated in a high, medium, or low fidelity manikin. Further,the various materials utilized for manufacturing the inserts, asoutlined above, are stable in a variety of environmental conditions, soshipping, storage, and/or use conditions have negligible impact on theproduct and how it functions.

Referring now to FIGS. 15 and 16, shown therein is a male genitaliamodel 250 according to an aspect of the present disclosure. The malegenitalia model 250 can be manufactured with varying degrees ofcomplexity for the development of models for catheterization, testicleself-examination (TSE), and/or circumcision. The model introducesimprovements to currently available male genitalia models byimplementing materials that provide a closer approximation to a humanpatient. Further, increased functionality, such as that required forTSE, can be introduced through the incorporation of a multi-layerstructure. In addition, a foreskin can be included in the model for thetraining of circumcision. Finally, the male genitalia model 250 can beattached to a high, medium, and/or low fidelity manikin and/or tasktrainer and/or it can be fixed on a support stand and soldindependently.

The male genitalia model 250 of the present disclosure provides a morerealistic alternative for the training of catheterization, TSE, and/orcircumcision. As shown in FIG. 15, the model 250 includes a backing orsupport layer 252, scrotum 254, and penis 256. An opening 258 extendsthrough the penis 256 to simulate the urethra. The backing 252 isincluded to allow the model 250 to be secured to either a manikin or asupport stand. In the case of a manikin, hook-and-loop fasteners and/orother suitable fasteners can be attached at designated locations to mateto corresponding hook-and-loop fasteners and/or other suitable fastenersthose on the manikin. For example, FIG. 16 shows hook-and-loop fasteners260 according to one arrangement of the present disclosure. Further,tubing can connect the opening 258 simulating the urethra outlet on themodel 250 to a urethra inlet of the manikin. In some embodiments, ananus opening or recess 262 is formed in the backing 252.

Referring now to FIGS. 17 and 18, the male genitalia are manufactured ina molding system 270. In that regard, the molding system 270 includes asupport stand or structure 272 that holds a mold 274 having an innercavity 276 shaped to form the male genitalia model 250. The mold 274 isconfigured to receive a shaft 278 that is utilized to form the opening258 that simulates the urethra. A sculpted model forms the basis of thegeometry for the inner cavity 276 of the mold 274, where detailing ofthe frenulum, sulcus, and skin texture of the penis and scrotum areincluded for improved realism. Due to the complexity of the geometry andthe extent of undercuts in the model, a nickel-deposition mold isutilized in some instances. The removable urethral shaft also aidsde-molding the model 250 from the mold 274. For a basic catheterizationor circumcision model, the mold is filled to the level of the back skinand allowed to cure. The basic model is purely for the training of malecatheterization. It incorporates soft, flexible materials that can beflexed and held in tension, but who recoil and return to their originalgeometry when released. The urethra can be catheterized with anycatheter of size 18FR or smaller. The entire model is manufactured fromone homogeneous material, so the properties are equivalent throughout.

In the case of a TSE model, an insert mold is manufactured to create thescrotal cavity. In some instances, an appropriately shaped insert moldis manufactured in a similar way as taught in U.S. patent applicationSer. No. 13/031,102, filed Feb. 18, 2011 and titled “Breast TissueModels, Materials, and Methods,” and U.S. Provisional Patent ApplicationNo. 61/305,982, filed Feb. 19, 2010 and titled “Polysiloxane Materialsand Methods that Mimic Tissue,” each of which is hereby incorporated byreference in its entirety. The scrotal area of the mold is clayed torepresent the scrotum skin. The thickness of the clay ranges from 2 mmto 8 mm, but in one embodiment is approximately 4 mm. The recommendedmaterial for the insert mold is an aluminum-filled urethane with a shorehardness of 88 D (Task® 18, Smooth-On, Inc., Easton, Pa.). The aluminumfilling aids the urethane in heat transfer, thereby improving themanufacturability. The cure time of platinum-cured silicones isdecreased at elevated temperatures. The TSE model can be incorporatedinto the basic model so that the scrotum area becomes a multi-layerconstruct that includes the testes, epididymis, spermatic cord, andtumors. By including a detailed epididymis, the difference between itand a tumor can be identified. For the circumcision model, a foreskin,that can be retracted to expose the glans, is included. The model can beused to train the steps in circumcision, including skin prep anddraping, excision of the foreskin, suturing, and wound dressing.

The flexibility of the catheterization model is critical to properfunction and realistic training. The urethra in a male has two 90° bendswhich make it difficult to catheterize. Therefore, to aid incatheterization, the penis is typically rotated so that it isperpendicular to the plane of the body. This removes one of the bends inthe urethral passage and assists the catheterization process. As aconsequence, the material selected for use in the model 250 must beflexible enough to rotate the penis 90° without kinking. The basiccatheterization model is manufactured as a single pour in someinstances. In some implementations, the model is manufactured from aplatinum-cured silicone thermoset or a platinum-cured silicone thermosetblend with a shore hardness as low as 00-10 but no higher than 30 A, andsilicone pigments are added to provide a realistic color match to light,medium, or dark skin tones. Lower durometer materials tend to be tackierand more susceptible to marking, so it is often beneficial to blend lowand higher durometer materials to make a compromise between flexibilityand durability. Inventors have found that a silicone blend featuring aplatinum-cured silicone thermoset with a shore hardness of 00-10(Silicone 99-255, Smooth-On, Inc., Easton, Pa.) and a platinum-curedsilicone thermoset with a shore hardness of 00-30 (Ecoflex® 0030,Smooth-On, Inc., Easton, Pa.) is the most successful for use in thebasic catheterization model. The recommended percentage of the 00-30ranges from 20-60% of the total weight, where the preferred percentageof 00-30 is 28%.

A sculpted model also forms the basis for the TSE model, where thedetailing of the penis, scrotum, and testicular assembly accuratelyrepresents the natural anatomy. The TSE model can be used to train bothcatheterization and TSE. Whereas a basic catheterization model may beformed of a single pour or layer, the TSE model is composed of threelayers, with the testicular assembly inserted in the second layer insome instances. The three layers include the 1) penis and scrotal skin,2) scrotal cavity, and 3) backing. The testicular assembly incorporatesthe epididymis, testes with embedded tumors, and spermatic cord. Thetestes are free to move within the scrotal cavity. The first layer thatforms the penis and skin is manufactured from a platinum-cured siliconeor silicone blend as detailed in the basic catheterization model. Thesecond layer forms the scrotal cavity. The second layer is manufacturedfrom a blend of platinum-cured silicone thermoset and silicone oil insome instances. For example, in some embodiments the silicone thermosethas a shore hardness as low as 00-10 but no higher than 00-30, and thesilicone oil is a polydimethyl siloxane with a viscosity between 80-110centipose. In one embodiment, the silicone thermoset has a shorehardness of 00-10 (Silicone 99-255, Smooth-On, Inc., Easton, Pa.) andranges from 50-90% of the total weight, and the silicone oil (TC-5005 C,BJB Enterprises, Tustin, Calif. or F-100, SILPAK, Inc., Pomona, Calif.)ranges from 10-50% of the total weight. The present inventors have foundthat the preferred blend to optimize the realism of the scrotum sets thepercentage of the thermoset to 67% and the percentage of the oil(TC-5005 C, BJB Enterprises, Tustin, Calif.) to 33%. This blend createsa layer that is soft and pliable and allows palpation of the testicles.In some embodiments, the TSE model can also include Vas Deferens, andthe model can be used for the training of no-scalpel vasectomy. Forsurgical procedures such as this, the model is disposable.

The third layer forms the backing or back skin. The purpose of thislayer is to encapsulate the scrotal cavity and testicular assembly. Thislayer is manufactured from a platinum-cured silicone thermoset or aplatinum-cured silicone thermoset blend with a shore hardness as low as00-10 but no higher than 30 A, and silicone pigments are added toprovide a color match to layer 1. It is best to match the durometer ofthe backing to that of the skin in order to maintain the sameflexibility throughout. The preferred material is a blend ofplatinum-cured silicone thermosets with the first thermoset with a shorehardness of 00-10 (Silicone 99-255, Smooth-On, Inc., Easton, Pa.) andthe second thermoset with a shore hardness of 00-30 (Ecoflex® 0030,Smooth-On, Inc., Easton, Pa.). As with the skin, the preferredpercentage of 00-30 is 28%.

In some embodiments, the testicular assembly is manufactured from aplatinum-cured silicone thermoset with a shore hardness as low as 00-20but no higher than 30 A. The testes, epididymis, and spermatic cord areeach manufactured from the same shore hardness material; however, thetumors shore hardness is higher in order to palpate the differencebetween a tumor, testicle, or epididymis. In some instances, thematerial used for the testicles, epididymis, and spermatic cord is aplatinum-cured silicone thermoset with a shore hardness of 00-30(Ecoflex® 0030, Smooth-On, Inc., Easton, Pa.). In some instances, thematerial used for the tumors is a platinum-cured silicone thermoset witha shore hardness of 10 A (Dragon Skin® 10 Medium, Smooth-On, Inc.,Easton, Pa.).

Like the basic catheterization model and the TSE model, a sculpted modelforms the basis for the circumcision model. The only difference betweenthis male genitalia model and those discussed above is the addition of aretractable foreskin. It is possible to include the foreskin for both abasic catheterization model and a TSE model, but when the model is usedas a circumcision trainer, the foreskin cannot be replaced, so it is a1-time use disposable model. The materials used for the circumcisionmodel are identical to those described in the basic catheterizationmodel and TSE model.

One suitable technique for manufacturing a male genitalia modelaccording to the present disclosure will now be described. No limitationis intended hereby and those skilled in the art will recognize that manydifferent modifications and/or alternative manufacturing techniques maybe utilized, including the use of alternative materials. In oneparticular embodiment, a male genitalia model is manufactured using thefollowing steps:

-   1) Manufacture of Tumors (Material: Dragon Skin 10 Medium)    -   a) Measure 30 g Part B, add 3 drops of FuseFX Tan Flesh, 12        drops of FuseFX Warm Rosy Skin, and 30 g of Part A    -   b) Mix and Vacuum until all bubbles are removed    -   c) Pour into silicone lump molds    -   d) Cure in a 100° C. Oven for 30 minutes    -   e) De-mold and clean with isopropanol-   2) Manufacture of Testicular Assembly    -   a) Clean the mold and liberally apply mold release    -   b) Place the tumors in their designated locations in the tumor        mold    -   c) Seal the mold in preparation for injection.    -   d) Prepare the Testicle Mixture (Material: Ecoflex® 0030)        -   i) Measure 30 g of Part B, 4 drops of FuseFX Light Skin, 4            drops of FuseFX Tan Skin, and 2 drops of FuseFX Warm Rosy            Skin.        -   ii) Mix and Vacuum until all bubbles are removed        -   iii) Place in Taper Tip syringe and inject into mold until            material flows from vent holes        -   iv) Cure in a 100° C. oven for 30 minutes    -   e) Remove from mold and coat testicles, epididymis, and tumors        with Vaseline-   3) Manufacture of Penis and Scrotal Skin    -   a) Clean the mold and liberally apply mold release.    -   b) Secure the urethral rod shaft in place    -   c) Prepare the skin mixture (Materials: Silicone 99-255 and        Ecoflex 0030)        -   i) Measure 100 g of Silicone 99-255 Part B, add 38.5 g            Ecoflex 0030 Part B, add 7 drops of FuseFX Light Skin, add 7            drops of FuseFX Tan Skin, add 6 drops of FuseFX Warm Rosy            Skin, and mix until a uniform color.        -   ii) Add 100 g of Silicone 99-255 Part A, add 38.5 g Ecoflex            0030 Part A        -   iii) Mix and Vacuum until all bubbles are removed    -   d) Pour the mixture into the mold making sure to start pouring        at the lowest point, which is the glans. Pour the entire        contents into the mold.    -   e) Slowly place the insert mold into position, making sure that        the material does not overflow onto the top of the insert mold    -   f) Allow to cure for 30 minutes at 100° C.    -   g) Remove the insert (leaving the skin in place) and clean the        inner surface of the skin with isopropanol to remove any mold        release residue.-   4) Manufacture of Scrotal Cavity    -   a) Orient the testicular assembly within the scrotal cavity    -   b) Prepare the cavity mixture (Materials: Silicone 99-255 and TC        5005C)        -   i) Measure 30 g of Silicone 99-255 Part B, add 30 g of TC            5005C, add 3 drops of FuseFX Light Skin, add 3 drops of            FuseFX Tan Skin, add 2 drops of FuseFX Warm Rosy Skin, and            mix until a uniform color.        -   ii) Add 30 g of Silicone 99-255 Part A        -   iii) Mix and Vacuum until all bubbles are removed    -   c) Pour the mixture into the mold so that it reaches the level        of the pour for the skin. Do not allow the mixture to over flow.    -   d) Allow to cure for 30 minutes at 100° C.-   5) Manufacture of Backing    -   a) Prepare the Backing Mixture (Materials: Silicone 99-255 and        Ecoflex 0030)        -   i) Measure 75 g of Silicone 99-255 Part B, add 28.9 g            Ecoflex 0030 Part B, add 5 drops of FuseFX Light Skin, add 5            drops of FuseFX Tan Skin, add 4 drops of FuseFX Warm Rosy            Skin, and mix until a uniform color.        -   ii) Add 75 g of Silicone 99-255 Part A, add 28.9 g Ecoflex            0030 Part A        -   iii) Mix and Vacuum until all bubbles are removed    -   b) Pour the mixture into the mold making sure to start pouring        at the lowest point. Fill the mold completely    -   c) Allow to cure for 30 minutes at 100° C.-   6) De-mold the model and attach the Velcro, and punch the hole for    the anus.    -   a) Remove the urethral shaft and gently remove the model from        the mold. Clean the mold release residue off the part.    -   b) Attach the loop Velcro, in the three locations shown below,        with a cyanoacrylate such as Loctite 401.    -   c) Punch a ⅛″ hole in the location shown below for the anus    -   d) Apply talc to the mold    -   e) Transfer to Quality Inspection.

An advantage of the male genitalia models of the present disclosure overpreviously available models is that the materials adopted allow farsuperior flexibility for catheterization. The penis can be manipulatedso that it is oriented 90° to the plane of the body, and no kinkingoccurs. This means that the model can be catheterized in an equivalentmanner to an actual patient. The incorporation of the differentsilicones has provided a model that closely approximates the naturalhuman tissue. Another advantage to this model is the increasedfunctionality. The catheterization model can be combined with a TSEmodel, providing a more inclusive model for training of men'shealthcare. In that regard, this model can be incorporated in existingmanikins and task trainers, or it can be used as a stand-alone package.Further, the model can include a foreskin for the training ofcircumcision. Studies have shown that male circumcision significantlyreduces the risk of acquiring HIV. Finally, the resulting models arehighly durable, so they can be used for multiple catheterization and TSEprocedures, but, at the same time, it is of low cost, so it can be adisposable option for circumcision training.

Many other products can be manufactured from materials similar to thosedisclosed herein for the male genitalia model and other tissue inserts.For instance, the soft platinum cured silicone thermosets and siliconethermoset blends can be applied in the production of simulated ostomies,cervices, birth canals, and skins so that realism is achieved. Ostomiesare manufactured from a platinum-cured silicone thermoset or siliconethermoset blend with a shore hardness as low as 00-10 but no higher than00-45. The preferred material is a blend of a 00-10 silicone thermoset(Silicone 99-255, Smooth-On, Inc., Easton, Pa.) with a 10 A siliconethermoset (Dragon Skin® 10 Medium, Smooth-On, Inc., Easton, Pa.) shorehardness platinum-cured silicone thermosets in a 3:1 ratio. Siliconepigments are added to provide a realistic color. Cervices aremanufactured from a platinum-cured silicone thermoset with a hardness aslow as 00-10 but no higher than 00-45. The preferred material for use inthe cervix is a 00-30 platinum-cure silicone thermoset (Ecoflex® 0030,Smooth-On, Inc., Easton, Pa.) with silicone pigments to achieve arealistic color match. Birth canals are manufactured from aplatinum-cured silicone thermoset with a shore hardness as low as 00-10but no higher than 00-45. The preferred material for use in the birthcanal is a 00-30 platinum-cured silicone thermoset (Ecoflex® 0030,Smooth-On, Inc., Easton, Pa.) with silicone pigments to achieve arealistic color match. It is also possible to embed targets of varyinghardness within the body of the birth canal. These targets or landmarkscan be used to represent the ischial spines, sacrum, or coccyx. Thetargets can be manufactured from platinum cured silicone thermosets witha hardness ranging from 10 A to 50 A, or harder durometer materials canbe implemented, such as urethane plastics of hardness 60 D to 85 D.Silicone skins are manufactured from a platinum-cured silicone thermosetwith a shore hardness as low as 00-30 but no higher than 30 A. Thepreferred material is a 00-45 platinum-cured silicone thermoset (TC5101, BJB Enterprises, Tustin, Calif.) with silicone pigments to achievea realistic color match. The benefits to implementing silicone as a skinsubstitute include improved texture and increased elasticity. Theimproved texture adds to the overall realism of the product by providinga skin that feels much like a human's, including equivalent resistanceto needle puncture. The increased elasticity and flexibility providegreater range of motion and, in the case of chest skins, improved chestrise under lower applied forces.

Referring now to FIGS. 19-32, aspects of a surgical insert according toan embodiment of the present disclosure will be discussed. Referringinitially to FIG. 19, shown therein is a patient simulator 300 that mayinclude one or more features similar to patient simulator 100 discussedabove. With respect to the current discussion, the patient simulator 300includes an abdominal opening 302 in its torso. In that regard, thepatient simulator 300 includes a tummy cover 304 that is configured tobe received within the opening 302 to form the abdominal region of thesimulator 300. In that regard, the tummy cover 304 includes an abdominalwall surgical insert 306. The following discussion will be focused onaspects of the abdominal wall surgical insert 306.

The abdominal wall surgical insert 306 is configured to be used insurgical manikins and/or task trainers. By using the insert 306, medicalstudents will be able to learn and practice surgical techniques in amore realistic setting. In some instances, the insert 306 utilizes amulti-layer design that includes skin, adipose, fascia, muscle andperitoneum membrane, making it a lifelike simulation tool in the medicalfield. Accordingly, in some instances layers of the insert 306 areformed in a similar manner to the layers of other tissue models of thepresent disclosure. In some implementations, the surgical insert 306provides medical students or other users with a faithful model of theabdominal wall to be used in surgical procedures such as: C-Sections,hysterectomies, laparoscopies and others where incisions in theabdominal wall are necessary. Users are able to place the surgicalinsert within a pre-made cavity in the abdominal region of the tummycover. The position of the opening or cavity in the tummy cover isoriented based on the desired procedure(s) to be taught. In someinstances, the tummy cover includes multiple openings and/or cavities toreceive multiple surgical inserts. As soon as the surgical insert issecured in place, medical students and personnel will be able to makeincisions in the abdominal wall that provide the feel and realism ofeach layer of tissue. In that regard, skin, subcutaneous, fascia, muscleand peritoneum layers are included in the insert, all exhibiting theappearance and feel of the natural human abdomen. Further, once theprocedure is completed, the user can also practice suturing techniquesas executed in a surgical setting on the surgical insert.

Referring now to FIGS. 20 and 21, the surgical insert 306 includesmultiple layers. In particular, the surgical insert 306 includes a skinlayer 308 that defines an outer surface of the insert. Underneath theskin layer 308 is a subcutaneous layer 310. As best seen in FIG. 21, arecess or undercut 312 is formed in the subcutaneous layer 310 adjacentthe skin layer 308. The undercut 312 is utilized to place and secure thesurgical insert 306 on the tummy cover in some instances. A fascia layer314 is positioned beneath subcutaneous layer 310. A muscle layer 316 isformed beneath the fascia layer 314. As shown, an opening 318 extendsthrough a central portion of the muscle layer 316 as will be discussedin greater detail in the context of FIGS. 25-30 below. Finally, aperitoneum layer 320 is formed underneath the muscle layer 316.

As shown in FIG. 20, each of the five layers of the abdominal wallsurgical insert (AWSI) is generally formed to follow an ellipticalpattern and approximate the thickness of the human anatomy. Anelliptical outline was chosen to account for the fact that mostC-section incisions are made using a transverse cut. In addition thecited pattern compliments the abdominal wall geometry, giving theoverall assembly a smooth appearance. Research was also completed inorder to estimate the thicknesses of the existing layers. Maximum andminimum depth values were identified for each layer, and fixed valueswere tested in order to produce suitable results in areas such as: easeof cut, feel, structural support and attachment to surrounding tissue.Similarly, various materials were identified to best simulate thenatural anatomy.

The skin layer 308 is the first layer of the abdominal insert 306.Silicone pigments are used to match the color of the artificial skin toany required skin color. In some embodiments, the skin layer 308 is madeas a blend of two platinum cure silicone thermosets of shore 00-30 and10 A hardness. This combination was found to be the most suitable forthis kind of application, offering good suture retention and propertexture while making incisions. Viscosity of the materials was alsoconsidered as this insert is manufactured by pouring. A proper viscositywas achieved by combining materials of low and high mixed viscosities atan appropriate ratio. The material with hardness 00-30 (Ecoflex® 00-30,Smooth-On, Inc., Easton, Pa.) has a mixed viscosity of 3,000 (cps). Insome instances, it is mixed at a percent by weight range of 25% to 75%with a harder material (such as, Dragon Skin® 10 medium, Smooth-On,Inc., Easton, Pa.) that is more viscous at a mixed viscosity of 23,000(cps). It is recommended that these materials are mixed at a 1:1 ratioor 50% each.

The subcutaneous layer 310 is the second layer of the abdominal insert306. Pigments are added to create a realistic appearance matching thehuman adipose tissue. This layer is made as a blend of three siliconecomponents in some instances. In one embodiment, the first silicone usedis a platinum cured silicone thermoset (Silicone 99-255, Smooth-On,Inc., Easton, Pa.) of shore hardness 00-10. The second component is asilicone oil (TC-5005 C, BJB Enterprises, Tustin, Calif.), which couldalso be substituted for F-100 (SILPAK, Inc., Pomona, Calif.). The lastcomponent of the blend is silicone foam (Soma Foama®, Smooth-On, Inc.,Easton, Pa.). Percentages by weight composition ranges were tested inorder to identify combinations best resembling the appearance and feelof the subcutaneous layer. Suitable tanges include: 40-55%% for Silicone99-255, 32-40% for the silicone oil and 8-18% for the silicone foam.After testing the percentages by weight compositions, the recommendedpercentages are: 50% Silicone 99-255, 32% TC-5005 C and 18% Soma Foama®.

The fascia layer 314 is the third layer of the abdominal insert 306 andit is manufactured as a two-level component. The first level consists ofa fabric like element. Different pre-manufactured materials can beutilized for this first level, some of these materials include: Tyvek®,Mylar®, Tissue, Ingress Bianco, Organza and Vellum. For the second levela silicone blend of platinum cured silicone thermosets is utilized insome instances due to its ability to interact with surrounding tissue.This silicone based blend needs to attach to the inner walls of themuscle layer in order to properly simulate human anatomy. Moreover,pigments are added to this silicone layer to match the appearance ofhuman fascia. In some instances, the fascia layer 314 is formed of by acombination of TC-5005 C (BJB Enterprises, Tustin, Calif.), Silicone99-255 (Smooth-On, Inc., Easton, Pa.), Ecoflex® 00-30 (Smooth-On, Inc.,Easton, Pa.), and Dragon Skin® 10 medium (Smooth-On, Inc., Easton, Pa.).Percentages by weight compositions used in testing include: 100%Ecoflex® 00-30 and a blend of Dragon Skin® 10 medium (ranging from50-65%), Ecoflex® 0030 (ranging from 25-30%), and Silicone Oil (rangingfrom 5-25%). The recommended composition for the fascia layer is 65%Dragon Skin® 10 medium, 25% Ecoflex® 0030 and 10% Silicone oil.

The muscle layer 316 is the fourth layer of the abdominal insert 306.The color of the human muscle is simulated by adding silicone pigmentuntil the desired match is obtained. This layer is made platinum curedsilicone thermosets and it is one of the key elements in the supportstructure of the abdominal insert. A harder material is preferred forthis layer; however, it is also important to consider the feel of thematerial. Thus ranges from 00-30 to 10 A hardness are considered goodselections in order to obtain the right balance between hardness andrealistic muscle texture. Materials utilized in some embodiments of themuscle layer at different percent compositions include a 100%composition by weight of Ecoflex® 00-30 (Smooth-On, Inc., Easton, Pa.),and a blend of 25%-75% Dragon Skin® 10 medium (Smooth-On, Inc., Easton,Pa.) and 25%-75% Ecoflex® 00-30. The recommended or preferredcomposition is a 1:1 ratio blend.

The peritoneum layer 320 is the fifth and final layer of the abdominalinsert 306. This layer is made using a blend of two platinum curedsilicone thermosets in some instances. A combination of Ecoflex® 0030(Smooth-On, Inc., Easton, Pa.) and Dragon Skin® 10 medium (Smooth-On,Inc., Easton, Pa.) is the preferred mixture for this layer. Differentpercentage compositions were considered for this blend. Ranges for bothsilicone components (Ecoflex® 0030 and Dragon Skin® 10 medium) wereselected at 25-75% of weight composition. Just as with the skin layer itis important to consider the viscosity of the materials due to the factthat this layer is manufactured by pouring. In addition this layer isextremely thin, measuring only 0.01″, in some instances, which addscomplexity to the manufacturing process. Taking the mentioned factorsinto consideration, in some instances the percent by weight of thisblend is 50% of Ecoflex® 0030 (Smooth-On, Inc., Easton, Pa.) and 50% ofand Dragon Skin® 10 medium (Smooth-On, Inc., Easton, Pa.). Since thenatural peritoneum layer in the human body is a clear thin membrane, nopigments are utilized because the silicone components used in this blendare translucent.

Generally, the thicknesses of the various layers of the surgical insert306 are selected to match the natural human anatomy. Accordingly, insome instances, the layers have thicknesses within the range set forthin Table 2 below and are formed of the corresponding material(s) listedin the table. However, it is understood that numerous other materialsand/or ratios of materials are utilized in the surgical insert in otherinstances to simulate these same layers.

TABLE 2 Exemplary Layer Type, Thickness and Sample Material Layer type:Thickness: Sample Material Breakdown: Skin 0.04″-0.08″ 50% Dragon Skin ®10 medium, 50% Ecoflex ® 0030 Adipose 0.50″-0.75″ 50% Ecoflex ® 0010,32% Oil, 18% Soma Foama Fascia 0.04″-0.08″ 65% Dragon Skin ® 10 medium,25% Ecoflex ®, 10% Oil + Organza Muscle 0.25″-0.50″ 50% Dragon Skin ® 10medium, 50% Ecoflex ® 0030 Peritoneum 0.01″-0.03″ 50% Dragon Skin ® 10medium. 50% Ecoflex ® 0030

The abdominal wall surgical insert 306 is manufactured in two separateparts using two multi-component molds in some instances. Referring nowto FIGS. 22 and 23, the first mold 330, which may be referred to as thesuperficial tissue mold, is shown therein. As shown, the mold 330includes a lower component 332 having a cavity 334 and an uppercomponent 336 configured to mate with the lower component. In thatregard, the upper component 336 includes a central opening 338 extendingtherethrough and a lip 340 surrounding the opening 338. The mold 330 isconfigured to make the skin and subcutaneous layers 308, 310. In thatregard, the lip 340 is configured to define the undercut 312 between theskin layer 308 and the subcutaneous layer 310. The bottom component 332includes openings 342 and the upper component 336 includes openings 344.The openings 342 and 344 are configured to interface with fasteners 346,348 that secure the upper and lower components 332, 336 together. Inthat regard, the mold 300 is assembled (i.e., the top and bottomcomponents 332, 336 are secured together with the fasteners 346, 348)before either layer is poured into the mold. Although second in layerorder of the resulting insert 306, the material for subcutaneous layer310 is poured first into the cavity 334 of the bottom component 332 andpart of the top component 336. The lip 340 will define a recess or voidin the subcutaneous layer 310 that becomes undercut 312. The desire tohave undercut 312 is what makes a two part mold desirable in thisinstance. The de-molding of such a silicone assembly would be verydifficult on a single component pouring mold. FIG. 23 illustrates theportion of the insert 306 resulting from mold 330. The mold design asdescribed above requires that the subcutaneous layer of the insert bepoured prior to the skin layer. In an alternative embodiment, a threecomponent mold in which the skin layer can be poured prior to thesubcutaneous layer is utilized.

Referring now to FIG. 24, the second mold 350, which may be referred toas the deep tissue mold, is shown therein. As shown, the mold 350includes a main component 352 that defines a cavity 354. A plurality ofprojections 356 extend upwards from cavity 354. In the illustratedembodiment the projections 356 are cylindrical. In some instances theprojections 356 are utilized to create opening through the fascia,muscle, and peritoneum layers 314, 316, and 320. The most critical partof this second silicone assembly is properly reproducing the inner wallattachment of the fascia layer 314 to the muscle layer 316. In order toachieve this task, the main component 352 includes structures 358 and360 on opposite sides of the component that define recesses 362 and 364,respectively. The recesses 362, 364 are configured to receive key stockinserts 366, 368. In that regard, the key stock inserts 366, 368 havedifferent sizes and this variation in size is utilized to ensure properattachment of the fascia 314 to the muscle 316. In one particulararrangement, stock insert 366 has a width of approximately 0.1905″, aheight of approximately 0.4405″, and a length of 12.000″, while stockinsert 368 has a width of approximately 0.1230″, a height ofapproximately 0.2480″, and a length of 12.000″. In some instances, theinserts 366, 368 are pre-manufactured zinc-plated steel key stockcomponents of different dimensions. In general, the largercross-sectional insert 366 is placed first in the recesses 362, 364 ofthe component 352 before pouring the muscle layer in order to producethe inner walls of the muscle. The smaller cross-sectional insert 368 isthen placed in the recesses 362, 364 of the component 352 to allow thefascia layer to attach to the inner walls of the muscle layer 316. FIGS.25-30 illustrate this process. For simplicity in illustration, the moldcomponent 352 is not illustrated. FIG. 25 shows the insert 366. Themuscle layer 316 is then formed around the insert 366, as shown in FIG.26. The insert 366 is then removed, as shown in FIG. 27, and replacedwith insert 368, as shown in FIG. 28. Because the insert 368 has asmaller cross-sectional profile than the insert 366, there is space 370between the insert 368 and the muscle layer 316. The material for thefascia layer 314 is then introduced and fills the space 370 between theinsert 368 and the muscle layer 316, as shown in FIG. 29. The insert 368is then removed leaving opening 318, as shown in FIG. 30.

The molds 330 and 350 are designed using 3D CAD programs (SolidWorks andRapidform), and prototypes of these molds are made in ABS for testing.The preferred material for production molds will be Aluminum 6061 due toits heat transfer and light weight properties. However, other suitablemold materials may be utilized.

One suitable technique for manufacturing an abdominal surgical wallinsert according to the present disclosure will now be described. Nolimitation is intended hereby and those skilled in the art willrecognize that many different modifications and/or alternativemanufacturing techniques may be utilized, including the use ofalternative materials. In one particular embodiment, an abdominalsurgical wall insert is manufactured using the following steps:

-   1. Manufacture of Subcutaneous Layer:    -   a) Clean mold and apply petroleum jelly to parts of the mold        which will be in contact with this layer    -   b) Attach the two parts of the mold (Superficial Tissue Top &        Bottom) using counter sunk and butterfly fasteners    -   c) Prepare Subcutaneous Mixture (Materials: TC-5005C, Silicone        99-255 and Soma Foama®)        -   a. Measure 180 g of TC-5005C, add 140.25 g of Silicone            99-255 Part A, add 67.3 g of Soma Foama® Part A, add 0.2 g            of Silc-Pig® Flesh tone pigment, add 4 drops of Silc-Pig®            Yellow pigment, and mix until blend is homogenous.        -   b. Add 33.7 g of Soma Foama® Part B, add 140.25 g of            Silicone 99-255 Part B        -   c. Mix for approximately 7 minutes at 72° F. until bubble            formation and blend begins to thicken.    -   d) Pour mixture into mold and gently mix until blend starts to        set    -   e) Allow the mixture to cure for approximately 1.5 hours    -   f) If foams expands trim as needed-   2. Manufacture of Skin Layer:    -   a) Clean Superficial Tissue Top part of the mold    -   b) Prepare Skin Mixture (Materials: Ecoflex® 0030 and Dragon        Skin® 10 Medium)        -   a. Measure 36.3 g of Ecoflex® 0030 Part A, add 36.3 g of            Dragon Skin® 10 Medium Part A and mix until blend is            homogeneous        -   b. Add 36.3 g of Ecoflex® 0030 Part B, add 36.3 g of Dragon            Skin® 10 Medium Part B, add 0.4 g of Silc-Pig® Flesh tone            pigment, add 1 drop of FuseFX Rosy Skin, add 2 drops of            FuseFX Light Skin and mix until blend is homogeneous.    -   c) Place mixture in vacuum until air bubbles are removed    -   d) Pour Skin mixture on top of the cured Subcutaneous layer        carefully, to prevent material overflow    -   e) Remove any additional bubbles created during the pouring of        mixture    -   f) Allow mixture to cure for approximately 3.5 hours at room        temperature.-   3. Manufacture of Peritoneum Layer:    -   a) Clean mold    -   b) Prepare Peritoneum Mixture (Material: Ecoflex® 0030, Dragon        Skin® 10 Medium)        -   a. Measure 19.0 g of Ecoflex® 0030 Part A, add 19.0 g Dragon            Skin® 10 Medium Part A, and mix until blend is homogenous        -   b. Add 19.0 g of Ecoflex® 0030 Part B, add 19.0 g Dragon            Skin® 10 Medium Part B, and mix until blend is homogeneous    -   c) Place mixture in vacuum until air bubbles are removed    -   d) Pour blend into the mold and remove any additional bubbles        created during the pouring process    -   e) Allow mixture to cure for 30 minutes at 66° C.    -   f) Clean top surface of layer with isopropanol and apply a        substantial amount of mold release-   4. Manufacture of Muscle Layer:    -   a) Apply petroleum jelly to the first zinc-plated steel key        stock insert (Insert A) on all surfaces    -   b) Place insert onto mold and in contact with top surface of        cured Peritoneum Layer    -   c) Prepare Muscle Mixture (Materials: Ecoflex® 0030 and Dragon        Skin® 10 Medium)        -   a. Measure 87.0 g of Ecoflex® 0030 Part A, add 87.0 g of            Dragon Skin® Medium Part A and mix        -   b. Add 87.0 g of Ecoflex® 0030 Part B, add 87.0 g of Dragon            Skin® Medium, add 0.6 g of Silc-Pig® Blood pigment and mix            until mixture becomes homogenous.    -   d) Place mixture in vacuum until air bubbles are removed    -   e) Pour blend into the mold and remove any additional bubbles        created during the pouring process    -   f) Allow mixture to cure for 30 minutes at 66° C.    -   g) Remove first insert from mold    -   h) Clean top surface of layer with isopropanol and apply a        substantial amount of mold release-   5. Manufacture of Fascia Layer:    -   a) Apply petroleum jelly to the second key stock insert        (Insert B) on all surfaces    -   b) Place insert onto mold and in contact with top surface of        cured Peritoneum Layer    -   c) Prepare Fascia Mixture (Materials: Ecoflex® 0030, TC-5005C,        Dragon Skin® 10 Medium)        -   a. Measure 8.25 g of Ecoflex® 0030 Part A, add 7.0 g of            TC-5005C, add 21.5 g of Dragon Skin® 10 Medium Part A and            mix        -   b. Add 8.25 g of Ecoflex® 0030 Part B, add 21.5 g of Dragon            Skin® 10 Medium Part B, add 0.2 g of Silc-Pig® White pigment            and mix until mixture becomes homogenous    -   d) Place mixture in vacuum until air bubbles are removed    -   e) Cut second layer of fascia (Material: Organza) to match        elliptical pattern    -   f) Place second layer fascia (Organza) on top of cured muscle        layer    -   g) Pour mixture into the mold and remove any additional bubbles        created during the pouring process    -   h) Allow mixture to cure for 30 minutes at 66° C.    -   i) Remove second insert from mold    -   j) Clean top surface of cured fascia layer with isopropanol-   6. Attachment of Skin & Subcutaneous (part 1) to Fascia, Muscle and    Peritoneum (part 2): Since the AWSI is manufactured in two separate    parts and final assembly of the silicone components is needed    -   a) Place Skin & Subcutaneous (part 1) on a flat surface with        Subcutaneous layer facing in the upward direction    -   b) Clean Subcutaneous layer using isopropanol solution    -   c) Place part 2 on a flat surface with the fascia layer facing        in the upward direction    -   d) Apply a thin coat of Sil-Poxy® silicone adhesive to Fascia        layer    -   e) Place fascia layer of part 2 in direct contact with        Subcutaneous layer of part 1    -   f) Allow adhesive to cure for approximately 12 minutes    -   g) Gently brush skin layer of AWSI with talc powder

Referring now to FIGS. 31 and 32, the abdominal wall surgical insert 306will include a support member 380 along with fasteners for support andattachment to the tummy cover. The support member 380 is made from anysuitable material such as ABS material, Polycarbonate, Polypropylene,and or other suitable materials. As shown, the support member 380includes an outer wall 382 and a lip 384. A plurality of structures 386are positioned around the perimeter of the support member 380 andinclude openings 388 extending therethrough that are configured toreceive fasteners. Generally, any type of fastener may be utilized, butin some embodiments a standard 8-32 nylon screws 390 having a length ofapproximately 1.5″ and 8-32 nylon acorn nuts are utilized to secure thesupport member 380 to the tummy cover, as shown in FIG. 32.

There are many ways of attaching the insert 306 to the vinyl tummycover. Two options will now be discussed, but no limitation is intendedthereby. In a first approach, the tummy cover is placed with pre-madeelliptical cavity and screw bosses on a flat surface, with the umbilicusfacing downward. The support member 380 is placed in direct contact withinterior part of tummy cover. The nylon screws or other fasteners areplaced through the screw bosses of the tummy cover and the support. Theassembly is then secured together using nylon acorn fasteners. Theassembly is then turned over such that the umbilicus is facing upwardand the surgical insert is placed through premade cavity in the tummycover and into engagement with the support. In some embodiments, theundercut 312 of the surgical insert mates with the lip 340 of thesupport member 380. In the second approach, the tummy cover is placedwith pre-made elliptical cavity and screw bosses on a flat surface, withumbilicus facing the down. The surgical insert is then placed with skinoverlap facing the downward direction to allow the skin to sit in bellowtummy cover's front surface. The nylon screws or other fasteners areplaced through the screw bosses of the tummy cover and surgical insert.The support member is then placed in direct contact with peritoneumlayer and through nylon screws. The assembly is then secured together byusing nylon butterfly fasteners.

A standard surgical manikin will include the surgical insert 306attached to the manikin's tummy cover. This type of insert can be usedin C-section, laparoscopic and open abdominal procedures. The standardinsert is a five layer elliptical insert; however, in special cases suchas in OB/GYN surgical procedures an additional layer to simulate theuterus may be added. C-section procedures may require an incision low inthe pelvic region such as the Pfannenstiel incision, thus the currentlocation of the abdominal wall cavity and/or the geometry of the insertmay be alter to increase the realism of the procedure. In such case,alternate support mechanisms can be put in place outside or within thesurgical insert. The addition of elastic straps, or embedded plasticmeshes can be used in the event that additional support is needed. Thisconcept will also be applied in the event that the location or geometryof the insert needs to be altered due to the demands of a laparoscopicprocedure.

Further, artificial blood can be added to the surgical insert in orderto enhance the realism of the surgical experience. The fact that thesilicone components used in this insert are hydrophobic in nature,presents an advantage when using water based artificial blood solutions.In that regard, the silicone encases drops of water based artificialblood solution as it cures. Accordingly, in some instances artificialblood drops are added to the uncured subcutaneous layer duringmanufacture. These blood casings are ruptured by a scalpel duringsurgery simulations, adding the bleeding component of a standardsurgical procedure.

Having a surgical simulator such as those described above offers greatadvantages over more commonly used surgical learning tools (use ofanimals and cadavers). The fact that the use of animals and cadaversrequire special permits and regulations, make the simulated surgicalinserts of the present disclosure more accessible and cost effectivethan their counterparts.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for other devices thatsimulate natural biological tissue, including human tissue. Inparticular, the materials and methods of the present disclosure may bereadily used in any application where the simulation of human skin, withor without underlying tissue structures, is desired. Such applicationsinclude, but are not limited to, manikins, sex toys, puppets, costumes,medical training devices, and/or other devices. Those skilled in the artshould also realize that such equivalent constructions do not departfrom the spirit and scope of the present disclosure, and that they maymake various changes, substitutions, and alterations to the embodimentsdisclosed herein without departing from the spirit and scope of thepresent disclosure. Also, it will be fully appreciated that theabove-disclosed features and functions, and variations thereof, may becombined into other methods, systems, apparatus, or applications.

What is claimed is:
 1. A method of forming a multi-layer tissuesimulation, the method comprising: forming a simulated skin layer in amold; forming a simulated fat layer over the skin layer in the mold;securing a simulated fascia layer to the simulated fat layer, whereinthe simulated fascia layer comprises a sheet of fabric-like material andcomprises a spunbonded olefin material; forming a simulated muscle layerover the simulated fascia layer in the mold; and forming a backing layerover the simulated muscle layer in the mold; wherein the simulatedfascia layer is secured to the simulated fat layer with a siliconadhesive.
 2. The method of claim 1, wherein the mold is sized and shapedsuch that the multi-layer tissue simulation represents a portion of atleast one of gluteus tissue, deltoid tissue, and thigh tissue.
 3. Themethod of claim 1, wherein the simulated skin layer comprises a siliconmaterial having a first hardness and the simulated fat layer comprises asilicon material having a second hardness, the second hardness beingless than the first hardness.
 4. The method of claim 3, wherein thesimulated fat layer comprises a silicon foam.
 5. The method of claim 3,wherein the simulated skin layer is cured prior to forming the simulatedfat layer.
 6. The method of claim 1, wherein the simulated skin layerand the simulated muscle layer comprise a common silicon material. 7.The method of claim 1, wherein the backing layer is pigmented to matchthe simulated skin layer.
 8. The method of claim 1, further comprising:removing the multi-layer tissue simulation from the mold; and insertingthe multi-layer tissue simulation into an opening in a portion of amanikin.
 9. A method of forming a simulated abdominal surgical wallinsert, the method comprising: forming peritoneum layer in a first mold;positioning a first insert within the first mold; forming a muscle layerwithin the first mold with the first insert positioned within the firstmold; removing the first insert from the first mold; positioning asecond insert within the first mold, the second insert being smallerthan the first insert; and forming a fascia layer within the mold withthe second insert positioned within the first mold.
 10. The method ofclaim 9, further comprising: forming a subcutaneous layer and a skinlayer in a second mold; and securing the subcutaneous layer and the skinlayer formed in the second mold to the peritoneum layer, the musclelayer, and the fascia layer formed in the first mold.
 11. The method ofclaim 10, wherein securing the subcutaneous layer and the skin layerformed in the second mold to the peritoneum layer, the muscle layer, andthe fascia layer formed in the first mold comprises: fixedly securingthe fascia layer to the subcutaneous layer.
 12. The method of claim 11,wherein a silicon adhesive is utilized to secure the fascia layer to thesubcutaneous layer.